Cellulose treated with di-vinyl sulfone to shrinkproof



Patented 3,, 1950 CELLULOSE TREATED WITH III-VINYL SULFONE T SHRINKPROOF Dwight L.

Naugatuck, Conn, Rubber tion or New Jersey Schoene and Victor assignors to United States Company, New York, N. Y.,

8. Chambers,

8 corpora- No Drawing. Application July 7, 1948,

Serial No. 87,507

4 Claims. (0]. 8116) 1 i This invention relates to modified cellulosic products.

An object of the invention is to provide products derived from cellulose, regenerated cellulose, such as viscose and rayon, and the like, which products .are dimensionally stable to water. A particular and outstanding object is to provide a method of reducing the shrinkage of cotton and regenerated cellulose textile materials and fabrics which are subject to washing. Another object is to provide fabrics havingcdmproved creaseresistance. Further'objects will be apparent from the hereinafter description.

found that the treatment with vinyl sulfone in. the presence of a basic catalyst substantially reduces the shrinkage of the rayon.

Although shrinkage is not so pronounced with cotton fabrics as with rayon, our process has definite application'to cotton also. When a cotton fabric is creased and then treated, it takes on the surprising property of returning ,to the same creased condition when wet. Similarly,

when a cotton or rayon fabric is pressed smooth Such effects can be applied in the manufacture of pleated or shaped fabrics, or in setting the twist in yarns. The treatment on both cotton and rayon is substantially the alkaline catalyst. The in a period ranging from a few seconds to about two hours, depending primarily upon the strength and concentration of the basic catalyst used. The reaction may be carried out from 0 .C. to 100 reaction is complete and temperatures of 0-50 C. are preferred. At the end of the reaction period, the fabric or yarn is washed substantially free ofcatalyst and limeacted vinyl sulfone, and then dried. Alternatively, the catalyst may be removed as such, byneutralization by dilute acid which eflectively stops the reaction. 7

We postulate the following reactionin the formation of vinyl sulfone-cellulose, although it is C. tion, we find it convenient not desired to be restricted to this mechanism: cellulose-0H cHl=cHs0,cH=-.cm HO-cliulose I catalyst cellulOSe-O-CHaOHrSOaCHgOHz-O-CelllllOSe where cellulose 0H represents part of the cellulose or regenerated cellulose chain.

The treated cellulose and rayon no longer dis solve in the usual solvents for these materials, such as cupra ammonia, and the quaternary in water or alkali solutions.

A number of variations in the treatment are possible without departing from the spirit and scope of the invention. The reaction may be carried out under anhydrous conditions;

Alternatively, the catalyst solutions may be pro-mixed and used for, the treatment. Advisedly, this latter procedure is used when the pre-mixing and treatment are accomplished in a period of a few minutes. Also, since in the presence of aqueous alkali, the vinyl sulfone will react very slowly with water at room temperatures, e. g., 20-25 0., such temperatures are preferred.

As catalyst, we may employ any base or alkali which is unreactive with vinyl sulfone. Ammonia,

sulfone and catalysts.

When a two-bath system ple, when the fabric is first sulfone bath. and

Q in a concentrated salt solution. Any salt such as sodium chloride, sodium sulfate, sodium acetate. sodium phosphate may be used, the purpose being that this reduces the leaching of the sulfone from the fabric into the catalyst solution.

The concentration of catalyst solution used depends upon the speed required in the reaction and upon the desire to avoid treatment by more concentrated alkali, which would tend to degrade the fabric. With cotton'fabrics, concentrations of alkali, such as sodium hydroxide of 20 to 30%, may be employed satisfactorily with a reaction time of 15 seconds or less. A- concentration of 0.5% will effect essentially the same reaction in a period of about 30 minutes. Concentrations ranging from 0.1% may be employed with somewhat longer reaction times. With fabrics con-- taining regenerated cellulose, high concentrations of alkali are to be avoided, because of their tendering effect. With such materials, sodium hydroxide concentrations ranging from 0.1% to about 8% may be employed satisfactorily. Similar considerations hold for the other catalysts.

Compounds capable of forming vinyl sulfone in situ under the conditions of the reaction also are to be considered as operative.

The concentration of the vinyl sulfone employed will depend upon the textile material, yarn, or filament used, and also from the desired use for the treated fabric.

An observable effect is obtained with as little as 0.1% based on the weight of the cellulose, and preferred concentrations lie between about 1 and 10%, although concentrations up to 1 part of vinyl sulfone per part of cellulose, by weight, may be used.

.As applied to fabrics, increasing concentrations of vinyl sulfone cause a progressive decrease in the tensile strength so it is desirable to keep the concentration as low as possible consistent with obtaining the desired effect. With regenerated cellulose, concentrations of vinyl sulfone between approximately 1 part and approximately 5 parts per 100 of the cellulose give satisfactory results with negligible tensile deterioration.

To obtain, for example, a 5% concentration of the sulfone on the fabric, it is convenient to dip the fabric into a 5% solution of the vinyl sulfone in water, and then pass it through rolls set at a tension to provide a wet pick-up of about 100%. The wet fabric is then passed through a solution of the basic catalyst in a concentrated aqueous salt solution and then through another set of rolls set to give a wet pick-up or about 120-200%. The fabric is allowed to stand until the reaction is substantially complete, and is then washed, dried, and finished according to normal textile finishing operations.

It has also been found that if the fabrics are impregnated or sized with textile sizing materials, such as starch, dextrin, methyl cellulose, carboxy methyl cellulose, polyvinyl alcohol, and various alkali soluble vegetable gums, such as gum arabic, and the like, that fabrics are obtained having permanent stiffness, improved hand, and in some cases improved crease-resistance, in addition to improved shrink resistance. This treatment is accomplished readily by simple procedures. For example, the fabric may be immersed in a solution or suspension of the sizing material and dried, leaving the fabric impregnated with the sizing. It is then treated with the vinyl sulfone according to the usual procedure. Part of the sulfone reacts with the cellulosic fabric and part often convenient to treat a. sized fabric with vinyl sulfone, thus achieving stiflness and dimensional stability at the same time.

The following examples are given to illustrate our invention, but are not to be construed as limiting thereto.

EXAMPLEI 'A plain weave viscose spun rayon fabric having a count of 54 x 53, a weight of 5.3 oz. per yard, and made of 16.3/1 warp and 16.4/1 filling of spun viscose staple fibre is passed through an aqueous impregnating solution containing 20 grams of vinyl sulfone in 1000 ml. of solution. The excess solution is removed by passing the rayon fabric through rolls set at such a pressure that the weight of the wet fabric is about twice the weight of the dry fabric, 1. e., a 100% wet pick-up. The wet fabric is then immersed in an aqueous solution containing about 10 grams of sodium hydroxide and 200 grams of sodium sulfate in 1000 ml. of solution. The fabric is again passed through squeeze rolls, the pressure of which is less than that of the rolls mentioned above. The fabric is then allowed to stand for at least 30 minutes at or near room temperature (ca. 25 C.). At the end of this time it is immersed in an aqueous solution containing pproximately 1% acetic acid to neutralize the alkali. The fabric is then washed in water and dried. Best results are obtained if the tension applied to the fabric during drying is sufllcient only to hold it in the dimensions maintained during treatment. The following table gives the results of laundering tests run with /z% of mild soap at F. for 15 minutes. The samples described as dried stretched are dried to their original dimensions after treatment, those described as dried relaxed, are dried hung on a line.

Percent warp shrinkage Washes 1 2 x 3 i 5 7 Untreated 8.4 7.7 10.8 9.7 14.6 Treated:

Dried Stretched. .1. 0 0.7 2. 8 2.1 4. 2 Dried Relaxed +0.3 +0.7 +0.7 0.3 2.1

Norm-The values for the "dried stretched" shrinkage mean that the sample after the treatment was dried in a stretched condition. ifter gzgshlng the drying was done relaxed. The values denote s re c g.

' EXAMPLE2 Percent warp shrinkage Washes 1 2 a a 1 Unttgidted 5.9 0.7 14.9 as; .9 Dried Stretched. as 4.9 4.5 as 6.2 Dried Relaxed o 1.1 0.3 +1.4 as

The value denotes stretching.

, least 30 minutes.

ple 1.

- lated through mums Percent warp shrinkage Washes 1 2 3 5 7 Untreated 6.0 0.7 14.0 26.4 31.0 Treated:

DriedStretched 2.1 2.1 2.8 1.4 218 Dried Relaxed +1.4 +1.7 +1.7 +2.4 1.1

A viscose rayon fabric, as described in Example l, is treated with vinyl sulfone and alkali, as described in Example 3. The table below presents the results of laundering tests:

Percent warp shrinkage Washes l 2 3 5 I 7 Untreated. 8.3 15.3 16.0

. Treated:

Dried Stretched. 1. l 1.4 0.3 0. 7 0. 3 Dried Relaxed.-- +1.4 +1.4 +0.3 +0.3 +0.8

EXAMPLE 5 A /1 all viscose spun rayon yarn wound on perforated tubes is impregnated with a 3% aqueous solution of vinyl sulfone in a, package dyeing machine. The excess solution is allowed to drain oil, and a. 2% aqueous sodium hydroxide solution containing sodium sulfate, is circuthe yarn. The yarn is allowed to stand for minutes, and the alkali is neutralized with dilute acetic acid. The dried, and woven into a fabric. This fabric has much less shrinkage than a fabric woven from an untreated yarn.

EXAMPLE6 A specially woven all cotton fabric with warp threads twisted into a coiled form. so that the material is highly elastic, is thoroughly wet with a freshly prepared aqueous solution containing 10 grams of vinyl sulfone and 0.5 gram of sodium hydroxide per 100 ml. of solution. The excess solution is allowed to drain of! and the material kept 50 C. for about one-half an hour in a closed container. The reaction is stopped by neutralizing the alkali with an excess of dilute acetic acid and the fabric is then washed with water and dried.

A strip 3 inches wide in the fill direction is wet with water and loaded with the weights indicated in the table below. The percent elongation in the warp direction resulting from this load and the percent increase in length remaining removed is given for each loadmg. It .can be seen from these figures that the treated fabric resists stretching to a much greater degree. It also returns to more nearly its original length after the load is removed than does the previous samples andthe yarn is washed.

Per Cent Elongation, treated- 9 Per Cent Elongation, control- Per Cent Bet, treated 5 5 Per Cent Set, oontroL. mm

Example 1, except that a 4% aqueous solution of vinyl sulfone is used in place of the 2% solution specified there. The neutralization with acid, washing, and drying are the same as described in lilrsample 1. The table below presents the resu w 1 Percent warp shrinkage with water. It is then spread out and pressed with a hot iron until it is only slightly moist. When the iron is lifted, the fabric snaps back into the original folds, i. e., approximately recovery. When pressing is continued to dryness, the fabric lies flat but the position of the original creases is still visible.

condition. This demonstrates how our treatment tends to fix" the fabric in its original dimensions. A similar but less pronounced effect is observed with regenerated cellulose.

EXAMPLE 9 solution containing about 20% sodiumsulfate, is used in place of the sodium hydroxide solution. The fabric is allowed to stand in contact with asses EXAMPLE A viscose rayon fabric, as described in Example 8, is treated in the same way as described in that example, except that a 2% aqueous solution of benzyltrimethyl ammonium hydroxide, containing about sodium sulfate, is used in place of the 5% aqueous sodium carbonate solution. The following table gives the results of laundering tests.

Percent warp shrinkage Washes i- 1 2 3 5 7 Untreated 8.3 9.0 10.0 12.2 13.6

Treated 2.8 2.8 6.2 4.2 3.5

EXAMPLE 11 fabric and then washed in water. It is stretched to its original dimensions and dried in this stretched condition. The finished fabric is subjected to a laundering test as in previous examples and the following table gives the results.

Percent warp shrinkage Washes 1 2 3 5 7 ggdfIIIIIIiIIIIIIIIIIIIIIII 31 2i; 22 if? it EXAMPLE 12 A piece of viscose rayon fabric is treated with 5% vinyl sulfone under the conditions of Example 11. At the end of the reaction the rayon does not dissolve in a 38% solution of benzyl trimethyl ammonium hydroxide, while an untreated .control dissolves in a few minutes;

A 4 oz. spun viscose rayon fabric is treated in the greige, without removing warp size, with a solution containing 3% vinyl sulfone and alkali catalyst, according to the procedure of Example 1. The treated fabric and a control are then laundered at 180 F. for 30 minutes, dried, and examined. The treated fabric shows only slight shrinkage and remains nearly as stiff as the original unwashed fabric, 1. e., the size is not removed. The washed control shows much more shrinkage and is less stiff due to removal of the size.

Having thus described our invention, what we claim and desire to protect by Letters Patent is: l. A method which comprises contacting and chemically combining cellulose and derivatives of cellulose containing cellulosic hydroxyl groups with divinyl sulfone.

1. A method which comprises subjecting cellulose to chemical reaction with divinyl sulfone.

3. A method which comprises contacting and chemically combining cellulose and derivatives of cellulose containing cellulosic hydroxyl groups with divinyl sulfone in the presence of a basic compound unreactive to divinyl sulfone as a catalyst therefor, which basic compound is from the class consisting of alkali-metal, alkali-earth metal, quaternary ammonium hydroxides, and alkali-metal carbonates.

4. A product of reaction of divinyl sulfone and cellulose fibres in which the fibre form of the cellulose is retained in the modified cellulose, said modified cellulose fibres being more resistant to shrinking by water than the untreated cellulose fibres.

DWIGHT L. SCHOENE.

VICTOR S. CHAMBERS.

REFERENCES CITED 'lhe following references are of record in the file of this patent:

' unrrnn s'rs'ms PATENTS- Number Name Date 2,969,774 Reid Feb. 9, 1937 2,103,879 Ufer Dec. 28, 1937 2,243,630 Honk et al. May 2'1, 1941 2,427,640 Whitehili et al. Sept. 16, 1947 

1. A METHOD WHICH COMPRISES CONTACTING AND CHEMICALLY COMBINING CELLULOSE AND DERIVATIVES OF CELLULOSE CONTAINING CELLULOSIC HYDROXYL GROUPS WITH DIVINYL SULFONE. 